1. Field of the Invention
The invention relates to a semiconductor device and a method of manufacturing the same, particularly, a semiconductor device manufactured by forming a groove in a semiconductor substrate from the front surface to the middle thereof in the direction perpendicular to the front surface and performing dicing thereto in a subsequent process, and a method of manufacturing the same.
2. Description of the Related Art
A chip size package is receiving attention in recent years as a new packaging technology. The chip size package is a small package having almost the same outside dimensions as those of a semiconductor die packaged in it.
Hereafter, an example of a structure of a BGA type semiconductor device which is one of the chip size packages will be described. As shown in FIG. 10, pad electrodes 112 are formed on a front surface of a semiconductor substrate 110 formed with an electronic device 110D with an insulation film 111 being interposed therebetween. A supporting substrate 114 made of single crystal silicon is attached to the front surface of this semiconductor substrate 110 so as to face it with an adhesive layer 113 being interposed therebetween. Openings 110A are then formed in the semiconductor substrate 110 along dicing lines DL. An insulation film 115 is then formed so as to cover the back surface of the semiconductor substrate 110 to the openings 110A. The pad electrodes 112 are then partially exposed, and wirings 116 are formed on the insulation film 115 so as to be connected to the exposed parts of the pad electrodes 112 and extend onto the back surface of the semiconductor substrate 110.
Then, grooves 117 are formed in the supporting substrate 114 from the front surface to the middle thereof in the direction perpendicular to the front surface, along the dicing lines DL inside the openings 110A. A protection film 118 is then formed so as to cover the back surface of the semiconductor substrate 110 to the grooves 117. Bump electrodes 119 are then formed so as to be connected to the wirings 116 through openings provided in the protection film 118. When this semiconductor device is mounted on electronic equipment, the electronic device 110D and an external circuit (not shown) mounted on a circuit board (not shown) such as a printed circuit board are electrically connected by connecting the bump electrodes 119 to a wiring pattern (not shown) on the circuit board.
A BGA type semiconductor device is described in Japanese Patent Application Publication No. 2008-130768.
In the method of manufacturing the semiconductor device described above, however, when the grooves 117 are formed in the supporting substrate 114, a region 114A of the supporting substrate 114 which is on an extension of the tip of the groove 117 may crack due to stress by contact of a dicing blade (not shown) to cause a fracture 114C separating the supporting substrate 114. The fracture 114C along the groove 117 of the supporting substrate 114 may also occur not only due to the stress by the contact of the dicing blade but also due to some stress occurring in the supporting substrate 114 in the process of forming the grooves 117 and processes after the formation of the grooves 117, for example, stress during handling.
It is conceivable that such a fracture 114C is caused by the fact that the dicing lines DL and dicing lines crossing perpendicularly thereto (not shown) extend in a direction that is parallel with cleavage planes of the crystal lattice structure of silicon, i.e., the face-centered cubic lattice structure, and the grooves 117 extend along these dicing lines DL.
Therefore, the supporting substrate 114 which is not to be diced at this time is practically diced along the dicing lines DL, and the protection film 118, the bump electrodes 119 and so on which need be formed after the formation of the grooves 117 can not be formed, thereby decreasing the yield of semiconductor devices.